Self-tapping tee

ABSTRACT

A self-tapping tee for heavy walled plastic pipe such as polyvinyl chloride (PVC) or thick walled polyethylene tubing. The self-tapping tee includes a saddle for gripping a tubular line to be tapped, a coupling tap with a stem for poking a hole in a sidewall of the line, with the sidewall of the line around the hole stretched about the stem, forming a seal, and a removable mandrel for supporting the stem while the hole is being made.

This is a division, of application Ser. No. 09/434,729, Nov. 5, 1999,U.S. Pat. No. 6,216,723 B1.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a self-tapping tee with a coupling taphaving a removable mandrel for use on heavy walled plastic pipe, such aspolyvinyl chloride (PVC) pipe or thick walled polyethylene tubing, saidself-tapping tee being useful without the mandrel on light walledplastic pipe or tubing.

2. Brief Description of the Prior Art

Plastic pipe is in common use in underground irrigation systems. Bothlight walled plastic pipe, such as polyethylene, and heavy walledplastic pipe, such as PVC and thick walled polyethylene tubing, areused. Heavy walled polyethylene tubing and PVC pipe have also beenapproved by various governmental agencies for natural gas.

With the advent of plastic pipe, it has been found that tapping toolsfor metal pipe are generally considered much too expensive for use withplastic pipe. Such tools for metal pipe are generally manufactured fromhigh priced steel which is carefully machined and heat treated. Inkeeping with the change to plastic pipe, various tool designs of lessexpensive construction have been proposed.

There are self-tapping tees, formed of plastic material, for lightwalled plastic pipe such as described in U.S. Pat. No. 5,694,972 to Kingfor Saddle Tee for Irrigation Lines. In this patent, a coupling tap ispoked through polyethylene tubing or the like, with the sidewall of thetubing around the hole stretched about the tap, forming a seal.

Conventionally, when a plastic tee joint is installed on heavy walledplastic pipe, such as PVC or thick walled polyethylene, a hole isdrilled or cut in the sidewall of the line. With a typical saddle teefor PVC pipe, glue is applied to the line, the saddle tee is snapped onthe pipe over the glue and a hole is drilled in the line through afitting after the glue has set. This operation is accompanied by somerisk that the coupon or filings cut from the sidewall may be washedthrough the line and plug a valve or sprinkler head downstream from thetap. In use with PVC pipe, the King patent mentioned above teachesdrilling a hole in the sidewall either before or after the tee isinstalled. Like other tee joints, the patent suggests gluing theself-tapping tee to the line and/or the use of o-rings or the like toensure a good seal.

BRIEF SUMMARY OF THE INVENTION

In view of the above, it is an object of the present invention toprovide a plastic, self-tapping tee for heavy walled plastic pipe. It isanother object to provide a self-tapping tee that does not require theremoval of material (e.g., filings or a coupon) from the sidewall of theline to establish the tap for the tee joint. Other objects and featuresof the invention will be in part apparent and in part pointed outhereinafter.

In accordance with the invention, a self-tapping tee for a tubular lineincludes a saddle, coupling tap and mandrel as more particularlydescribed below. The saddle has a centrally bored housing mounted on aclamp for gripping the line being tapped, said housing having internalthreads. The coupling tap has a stem attached to a hollow fitting, saidstem being hollow and having at least one opening in the stem. Thefitting is externally threaded and cooperatively received in theinternal threads of the housing and the coupling tap has a lengthgreater than the length of the housing. The mandrel is received in thehollow of the stem and removably attached to the coupling tap.

In use, the mandrel advances with the coupling tap as it is threadedinto the housing of the saddle. The mandrel reinforces the stem of thecoupling tap as it is pressed against the line being tapped and pokes ahole in the sidewall of the line, said mandrel thereafter being removedfrom the coupling tap.

The invention summarized above comprises the constructions hereinafterdescribed, the scope of the invention being indicated by the subjoinedclaims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

In the accompanying drawings, in which several of various possibleembodiments of the invention are illustrated, corresponding referencecharacters refer to corresponding parts throughout the several views ofthe drawings in which:

FIG. 1 is an exploded perspective view showing a self-tapping tee inaccordance with the present invention, said self-tapping tee including amandrel, coupling tap and saddle;

FIG. 2 is a side elevation, partly in section, showing the mandrel,coupling tap and saddle installed on a line;

FIG. 3 is a side elevation showing the mandrel being withdrawn from thecoupling tap after the coupling tap and saddle have been installed onthe line;

FIG. 4 is a side elevation showing the coupling tap and saddle installedon a smaller line;

FIG. 5a is a detail on an enlarged scale taken along line 5 a-5 a inFIG. 3 showing how the sidewall of the line about the hole poked by thecoupling tap is stretched around the stem of the tap forming a seal;

FIG. 5b shows a seal with the addition of an o-ring;

FIG. 5c shows a seal with the addition of glue;

FIG. 6 is an exploded perspective view showing a driver for the mandrelwith the same coupling tap as shown in the previous drawings but with adifferent saddle;

FIG. 7 is an exploded view of a driver-mandrel combination illustratedin use with a coupling tap having a truncated stem;

FIG. 8 is a perspective view on an enlarged scale of one of twoidentical halves of the saddle shown in FIG. 6;

FIG. 9 is an exploded side elevation of another self-tapping tee with adifferent mandrel, coupling tap and saddle than shown in the otherfigures;

FIG. 10 is a side elevation of a further coupling tap; and,

FIG. 11 is a cross-section taken along line 11—11 in FIG. 9.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings more particularly by reference character,reference numeral 10 refers to a self-tapping tee for use in tappingheavy walled plastic pipe such as PVC and thick walled polyethylenetubing. The term “heavy walled” refers to plastic pipe or tubing that isdifficult to penetrate because of the material of which it is made(e.g., PVC) or because of wall thickness (e.g., thick walledpolyethylene, polypropylene, polybutylene or the like). “Light walled”pipe or tubing refers to polyethylene tubing having a wall thickness upto about 0.100 inch, as well as other materials having a similarresistance to puncture. By way of example, but not limitation, heavywalled pipe includes Class 160 and 200 PVC pipe and polyethylene tubinghaving a wall thickness between about 0.135 and 0.200 inch.

Self-tapping tee 10 in major part includes a saddle 12, a plasticcoupling tap 14 and a mandrel 16. Saddle 12 has a housing 18 mounted ona clamp 20 for gripping a line 22 being tapped. As more particularlydescribed below, clamp 20 preferably closes around line 22 but may gripthe line sufficiently without encircling it if the clamp is glued to theline. Housing 18 has a central bore 24 and internal threads 26. Threeillustrative saddles 12 (FIGS. 1-4), 12′ (FIG. 6) and 12″ (FIG. 9) areshown in the drawings, the invention, however, is not limited to theparticular saddles shown as will become more apparent. Saddle 12, asshown in FIGS. 1-4, and saddle 12″ as shown in FIG. 9 are described inU.S. Pat. No. 5,694,972 to King.

Clamp 20 has a pair of opposing, arcuate clamp segments 28 having upper,lower and intermediate portions 28U, 28L, and 28I, respectively. Clampsegments 28 are attached on opposite sides of housing 18. Each segment28 as shown in FIGS. 1-4, or at least one segment, of clamp is hinged at30 along its intermediate portion 28I, opposite the clamp segment whichit opposes, to an arm 32 which depends from housing 18. As shown in thedrawings, hinge 30 is closer to upper portion 28U than lower portion28L, facilitating entry of line 22 through the gap between the opensegments. As saddle 12 is pressed on line 22, the pipe or tubing makescontact with upper portions 28U, causing lower portions 28L to pivotabout 30, closing the clamp. Each of segments 28 has a locking part 34at the free end of its lower portion 28L, cooperating with the lockingpart at the free end of the lower end portion 28L of the other clampsegment. Both locking parts 34 are of a substantially hook-likeconfiguration, one curved inwardly and the other curved outwardly forinterengagement. Locking parts 34 provide locking means forinterconnecting the clamp segments without tools when the clamp ispressed onto line 22 and may have several locking positions for use withdifferent diameter pipe or tubing, over a selected range.

Saddle 12″, shown in FIG. 9, is like saddle 12 except that arms 32″ areelongated, for use as described below, and clamp segments 28″ (28″U,28″I and 28″L) are smaller to accommodate smaller diameter pipe. Saddle12″ is particularly designed for use with smaller diameter pipe or thelike.

Saddle 12′, as shown in FIG. 6, is formed of two identical sections 12a′ and 12 b′, one of which (12 a′) is shown in FIG. 8. Coupled together,sections 12 a′ and 12 b′ form a cylindrical housing 18′ divided into twoidentical housing sections 36′, 38′ and a clamp 20′ divided into twoidentical clamp sections 40′, 42′. Like saddle 20, housing 18′ has acentral bore 24′ with internal threads 26′ and is mounted on clamp 20′.At the parting line between housing sections 36′, 38′, one side isoutfitted with a female latch member 53′, while the other side isoutfitted with a male latch member 55′. Female latch member 53′ has apair of spaced sidewalls 57′ and male latch member 55′ has a resilienttongue 59′ and a head 61′ designed to latch between sidewalls 57′. Atthe bottom parting line between clamp sections 40′, 42′, one side isprovisioned with a radially, outwardly extending rib 44′, while theother side is provided with a second radially, outwardly extending rib46′, a free end of which is hooked over to form a groove 48′. When selfmating members 12 a′ and 12 b′ are slid together, rib 44′ of each memberis received in groove 48′ of the other at the bottom of clamp 20′ andmale latch member 55′ is received in female latch member 53′ of theother along the sides of sections 36′, 38′ keeping saddle 12′ assembled.Coupling tap 14 will also keep the sections together as the tap isscrewed into the saddle as more particularly described below.

Use of identical sections for saddle 12′ reduces production costs sinceonly one parting mold is necessary to make both members and there is nocore to be unscrewed. It also eliminates the need to search for matingmembers since a user always has a mating pair, if he has two sections.On the other hand, saddle 12′, unlike saddle 12, cannot be used on arange of different diameter lines 22.

Coupling tap 14 may be made of metal but plastic is preferred andincludes a hollow fitting 50 attached to a stem 52. Stem 52 is hollowand has at least one opening 54 in the stem. Fitting 50 is externallythreaded 56 and is cooperatively received in internal threads 26 ofhousing 24, 24′ or the like. When fitting 50 has internal threads 58, itmay be used for coupling a branch line, riser or the like. When fitting50 has no threads, a branch line can be slip fitted into hollow fitting50 and glued. Stem 52 is conically tapered towards a first end 60 andattached to fitting 50 at a second end. When stem 52 comes to a point62, the point is preferably closed, with opening 54 located above. Atransverse reinforcing web 64 may be provided in point 62. As shown inFIG. 7, the tip of stem 52 may be truncated for use as describedhereinafter. In the form illustrated, fitting 50 is a cylinder, largerin diameter than stem 52, forming an abutment shoulder 66 at thejunction therebetween. Fitting 50 is preferably provided with one ormore wing grips 68 located on its periphery to aid a user in twisting itinto saddle 12, saddle 12′ or the like. In other instances, coupling tap14′ as shown in FIG. 10 may be a hollow fitting 50′ with barbs 51′. Afurther variation on coupling tap is shown in FIG. 9 wherein couplingtap 14″ has an abutment shoulder 67″ on stem 52″ and an annular seal 69″such as an o-ring or step grommet. Abutment shoulder 67″ spaces annularseal 69″ (e.g., step grommet) a selected distance from fitting 50″ forbetter sealing around the hole punched in the sidewall of line 22.Abutment shoulder 67″ also works in concert with upper portions 28″U ofclamp 20″ as a lock to prevent coupling tap 14″ from laterally wobblingin saddle 12″ and possibly breaking the seal.

Mandrel 16 has a shaft 70 that is received in hollow stem 52 of couplingtap 14 for reinforcement of the stem while coupling tap 14 is poking ahole 72 in line 22. Shaft 70 is sized for close fit in stem 52 and thetip of shaft 70 may be slotted 74 for receipt over web 64 (if present).Mandrel 16 may be slipped or threaded into stem 52 and is removablyattached to coupling tap 14. When coupling tap has wing grips 68, shaft70 is attached to a cap 76 with a pair of downwardly depending arms 78which push on grips 68 as coupling tap 14 is screwed into housing 18. Asseen in FIGS. 1 and 6, each of arms 78 includes a horizontally extendingfinger 80, pointing in a direction for embracing the underside of grips68 as coupling tap 14 is screwed into housing 18. The force applied togrips 68 may be increased when arms 78 extend beyond the ends of grips68, thus increasing the applied torque.

Referring now to FIG. 9, a second mandrel 16″ is shown, which may bemolded entirely of plastic. In this view shaft 70″ is formed from twointersecting blades 71″, mandrel 16″ being otherwise similar to mandrel16.

Coupling taps 14, 14′ and 14″ are preferably made of a hard plastic suchas ABS, nylon, PVC or the like, while saddles 12, 12′ and 12″ may beformed of a less rigid material such as polyethylene. It will beunderstood, however, that coupling taps 14, 14′ and 14″ and saddles 12,12′ and 12″ may be formed of other functionally suitable materials notpreviously mentioned such as metal. Mandrel 16 may be formed entirely ofmetal or partly of metal, for example with shaft 70 formed of a hardplastic such as used for coupling tap 14. Suitable mandrels are alsoillustrated by mandrel 16″ formed entirely of plastic.

In use, saddle 12 is attached to heavy walled line 22 where a tee jointis desired. Coupling tap 14 is threaded into housing 18 until grips 68are stopped by barbs 96 on housing 18. As coupling tap 14, with mandrelattached, is screwed into the housing, point 62 of stem 52 or shaft 70(when stem is truncated) contacts a sidewall of line 22 and pokesthrough, the sidewall of the pipe or tubing around the hole stretchedabout the point, forming a seal 82, best seen in detail FIG. 5a. Oncethis seal has been achieved, mandrel 16 may be withdrawn from couplingtap 14 and a branch line or the like threaded into fitting 50. Withsaddle 12′, as coupling tap 14 is threaded into housing 18′, matingmembers 40′, 42′ of clamp 20′, are locked together and cannot be slidapart, otherwise both saddles function the same.

Coupling tap 14″, saddle 12″ and mandrel 16″ as shown in FIG. 9 are usedin a similar manner to their counterparts described above except thatseal 82 is augmented by step grommet 69″ or an o-ring 69 as shown inFIG. 5b. Glue 73 may be also be used, as shown in FIG. 5c, with any ofthe coupling taps (14, 14′, 14″ or the like). Saddle 12″ which is spacedbelow housing 18″ by arms 32″ permits the use of the same lengthcoupling tap 14″ for a range of different sized lines 22. This isadvantageous when line 22 is made of stiff walled material such as PVC.When line 22 is flexible, as shown in FIG. 4, clamp 20 may pinch theline into an oval shape in cross-section, thereby facilitating the useof coupling tap 14 which would otherwise be too long and pierce bothsides of the line.

As shown in FIG. 6, a driver 84 may be used for reaching mandrel 16 whenself-tapping tee 10 is installed on a line 22, for example, deep withina hole. Driver 84 includes a long handled shaft 86 with a t-bar 88attached at a first end and with a head 90 at its second end. Head 90may be slotted at 92 such that it straddles grips 68 and arms 78. Itwill be understood that t-bar 88 increases the length of the lever arm,thus amplifying the force applied to coupling tap 14. Another variationis shown in FIG. 7. In this instance shaft 70 of mandrel 16 isintegrally formed with a shaft 86′ of a second driver 84′. Cap 76, arms78 and fingers 80 are eliminated and outwardly flared legs 94′ attachedto shaft 86′. As will be apparent, legs 94′ can be used to push grips 68in the same manner as arms 78 with t-bar 88′ amplifying the appliedforce. When the tip of stem 52 is truncated, as shown in FIG. 7,withdrawal of mandrel 16′ increases the flow of water through stem 52and line 22 as compared to a coupling tap with a closed point.

When line 22 is light walled, self-tapping tee 10 may be used withoutmandrel 16 in the manner described in U.S. Pat. No. 5,694,972 to King.Hence only coupling taps and saddles need be inventoried by the user,making tee joints on both light walled and heavy walled pipe or tubing.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained. Asvarious changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:
 1. A saddle for a tubular line, said saddle formedof two substantially identical sections, each section comprisingone-half of a cylindrical housing mounted on one-half of a cylindricalclamp, each one-half of the cylindrical housing having a female latchmember on one side of the parting line between the halves, said femalelatch member having a pair of spaced sidewalls, and a male latch memberon the other side, said male latch member having a resilient tongue anda head designed to latch between the spaced sidewalls of the femalelatch member, and each one-half of the cylindrical clamp, at the bottomparting line between the halves, having a portion with a radially,outwardly extending rib and a portion with a second radially, outwardlyextending rib with a tree end hooked over to form a groove for receiptof the first rib of the other section, whereby said sections areassembled first by sliding interaction of said first rib in the grooveof the second rib of the other section at the bottom parting line of thecylindrical clamp about the tubular line and thereafter latchinginteraction of the male latching member in the female latching member ofthe other section at the parting line between of the cylindrical housingto fixedly secure the saddle about the tubular line.
 2. The saddle ofclaim 1 wherein the cylindrical housing has a threaded portion forreceiving a coupling.